Convection oven appliances generally include a cabinet that defines a cooking chamber for receipt of food items for cooking. Heating elements are positioned within the cooking chamber to provide heat to food items located therein. The heating elements can include a bake heating element positioned at a bottom of the cooking chamber and/or a broil heating element positioned at a top of the cooking chamber. Convection oven appliances also include a convection heating assembly, which may include a convection heating element and fan or other mechanism for creating a flow of heated air within the cooking chamber.
During operation of convection oven appliances, food items within the cooking chamber are heated through various heat transfer mechanisms. Such mechanisms include: (1) radiation from oven walls, an oven door, and/or any exposed heating elements in the cooking chamber; (2) various convection mechanisms; and (3) conduction from a surface supporting the food items, e.g., a rack. Radiant heat transfer can provide a significant portion of the heat transferred to food items within the cooking chamber when the oven appliance is at a steady-state operating temperature.
Generally, oven appliances are preheated prior to inserting food items into the appliance's cooking chamber. Such preheating can be necessary to heat the oven appliance's walls, doors, and other exposed surfaces and bring the oven appliance up to the steady-state operating temperature. Prior to such preheating, radiant heat transfer from such components can be insufficient or unsuitable to properly cook food items within the cooking chamber. In reaching the operating temperature, common oven preheat algorithms attempt to reduce the overall preheat time while maintaining proper heat balance—i.e., the ratio of heat delivered from different areas of the oven. Failure to maintain proper heat balance can necessitate the extension of the preheat time. For example, if the preheat cycle relies largely on the high-power broil heating element to preheat the cooking chamber, the top portion of the food items may cook more quickly than the bottom portion of the food items due to the heat imbalance relative to the lower portion of the cooking chamber.
To avoid such heat imbalance, a user generally waits for the cooking chamber to reach the operating temperature and the preheat time may need to be extended to reach proper heat balance before inserting food items into the cooking chamber. Placing food items within the chamber too early may cause them to cook improperly. However, waiting for the oven to reach steady-state can consume a significant amount of the user's time. For example, preheat cycles can take over ten minutes to complete. In addition, valuable energy is consumed during preheating cycles that could be used to cook food items.
Accordingly, an apparatus or method for decreasing the preheat time of an oven appliance would be useful. More particularly, a preheating algorithm that reduces preheat time while maintaining proper heat balance within the cooking chamber would be especially beneficial.